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Old August 4th 17, 04:35 PM posted to uk.radio.amateur,uk.rec.models.engineering,rec.radio.amateur.homebrew
rickman rickman is offline
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First recorded activity by RadioBanter: Nov 2012
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Default A mechanical phase locked loop!

Jeff wrote on 8/4/2017 4:58 AM:


I don't know what you guys are seeing. The two pendulums of the Shortt
clock are in lock step. The fact that they are only compared every 30
seconds does not change the nature of the design.



What we are seeing is that even after the 30 second 'kick' the 2 pendulums
are NOT in phase.

They may well be 'a bit closer' in phase, but the kick just moves the
difference a fixed small amount in one direction, which may be sufficient to
bring the phases closer, or it may be too much and go through the in phase
point. With the design there is no time where the 2 pendulums are *held* in
phase.

The design in fact relies on the fact that the phase of the 2 pendulums is
constantly changing.


As is true for any PLL.

--

Rick C